Table 3 Sleep and heart rate variability measures at baseline and after 12 weeks for the equal-attention control and behavioral modification groups.
| Sleep Measures | Equal-Attention (n=14) | Behavioral Modification (n=13) | P-between | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Baseline | 12 Weeks† | Change | P-within | Baseline | 12 Weeks‡ | Change | P-within | ||
| PSQI | 4.9 (3.0) | 3.1 (1.5) | −1.7 (3.1) | 0.049 | 4.5 (2.7) | 3.0 (1.3) | −1.5 (2.9) | 0.063 | 0.830 |
| MEQ | 39.0 (8.1) | 40.4 (8.1) | 1.4 (2.7) | 0.070 | 37.2 (6.8) | 38.9 (5.3)† | 1.8 (2.7) | 0.044 | 0.322 |
| SHI | 17.1 (5.5) | 16.5 (4.2) | −0.6 (4.2) | 0.577 | 17.2 (4.5) | 15.2 (2.6) | −2.0 (4.3) | 0.121 | 0.416 |
| TST (hrs) | 6.5 (0.7)‡ | 6.9 (0.6)‡ | 0.4 (0.7) | 0.119 | 6.7 (0.6)# | 6.9 (1.0)# | 0.2 (1.1) | 0.237 | 0.898 |
| TIB (hrs) | 7.3 (0.8)‡ | 7.4 (0.8)‡ | 0.1 (0.7) | 0.619 | 7.6 (0.4)# | 7.7 (1.0)# | −0.1 (1.1) | 0.604 | 0.816 |
| SE (%) | 88.7 (5.9)‡ | 92.6 (4.7)‡ | 3.9 (4.3) | 0.015 | 88.6 (7.1)# | 89.8 (7.2)# | 1.2 (8.0) | 0.866 | 0.368 |
| HRV Measures | Equal-Attention (n=16) | Behavioral Modification (n=15) | P-between | ||||||
| Baseline | 12 Weeks† | Change | P-within | Baseline | 12 Weeks‡ | Change | P-within | ||
| fC (beats/min)§ | 68.1 (1.9) | 67.2 (1.8) | −0.9 (1.6) | 0.031 | 69.3 (1.3) | 67.2 (2.1) | −2.1 (2.2) | 0.002 | 0.104 |
| SDNN (ms) | 60.7 (4.8) | 63.5 (3.9) | 2.8 (3.0) | 0.002 | 59.5 (4.1) | 63.0 (4.3) | 3.5 (3.5) | 0.002 | 0.446 |
| RMSSD (ms) | 53.8 (3.9) | 56.5 (3.4) | 2.7 (3.5) | 0.008 | 52.7 (4.8) | 57.5 (3.3) | 4.8 (4.3) | 0.001 | 0.086 |
| HF (ms 2 )§ | 43.0 (2.9) | 43.2 (2.0) | 0.3 (2.3) | 0.616 | 40.1 (3.0) | 42.7 (1.5) | 2.6 (3.3) | 0.010 | 0.036 |
| LF (ms 2 ) | 53.6 (2.3) | 52.3 (2.5) | −1.3 (2.7) | 0.075 | 53.6 (2.1) | 51.0 (3.0) | −2.6 (2.8) | 0.003 | 0.197 |
| LF/HF | 2.6 (0.4) | 2.4 (0.4) | −0.2 (0.2) | 0.002 | 2.6 (0.5) | 2.1 (0.4) | −0.5 (0.8) | 0.007 | 0.740 |
Values are mean (SD). PSQI=Pittsburgh Sleep Quality Index; MEQ=Morningness-Eveningness Questionnaire; SHI=Sleep Hygiene Index; TST=total sleep time derived from sleep diary; TIB=time in bed; SE=sleep efficiency (TST/TIB); HRV=heart rate variability; fC=heart rate; SDNN=standard deviation of normal-to-normal intervals; RMSSD=root mean square differences of the standard deviation; HF=high-frequency component; LF=low-frequency component; LF/HF=ratio of low- to high-frequency components; †n=12; ‡n=10; #n=9; §significantly different at baseline ( P <0.05).